Based on the available information, muscle pain can be a side effect of taking Lipitor, a medication used to treat high cholesterol. This side effect is classified as a musculoskeletal condition, which also includes joint pain and weakness [3].

The Mayo Clinic states that "statin muscle symptoms can be distressing, but they're usually not serious" and that "the symptoms usually go away a few weeks after you start taking the medication or after your dose is adjusted" [2]. WebMD also notes that "muscle pain while taking a statin is usually minor and doesn't lead to any permanent damage" [1].

However, it is important to note that in rare cases, muscle pain can be a sign of a serious condition called rhabdomyolysis, which can cause kidney damage [2]. If you experience severe muscle pain, dark colored urine, or unexplained weakness while taking Lipitor, you should contact your healthcare provider immediately [2].

In summary, muscle pain can be a side effect of taking Lipitor, but it is usually not serious and goes away on its own. However, if you experience severe muscle pain or other symptoms, you should contact your healthcare provider.

Sources:
[1] <https://www.webmd.com/cholesterol-management/statins-managing-muscle-pain>
[2] <https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/statin-side-effects/art-20046013>
[3] <https://www.drugpatentwatch.com/p/tradename/LIPITOR>